Damping valves and shock absorbers

Abstract

To provide a valve which enables reduction of an entire length and improvement of assembly at low costs, and to provide a shock absorber.SOLUTION: A damping valve 1 of the invention includes: a valve seat member 2 including an annular recessed part 2d, a port 2c which is open on a bottom part 2d1 of the recessed part 2d, an annular valve seat 2e erected from an outer periphery of the recessed part 2d, and an annular facing part 2f having an inner peripheral surface facing the recessed part 2d; an annular sub valve 3 which is disposed spaced apart from the bottom part 2d1 of the recessed part 2d in the recessed part 2d and forms an annular gap P between an outer peripheral surface and the facing part 2f and in which the outer periphery side serves as a free end to allow deflection in a direction away from the valve seat member 2 in the recessed part 2d; and an annular leaf valve 4 which is laminated on the non-valve seat member side of the sub valve 3, spaced apart from the sub valve 3 in an axial direction and in which the outer periphery side serves as a free end to allow deflection and thereby enable the leaf valve 4 to separate from or be seated on the valve seat 2e.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a damping valve and a shock absorber.

Background Art

[0002] Conventionally, a damping valve has been used, for example, to generate a damping force by providing resistance to the flow of a liquid that occurs when a shock absorber expands and contracts. Among such damping valves, there is one that includes an annular valve body whose inner circumference is fixed to a piston rod and is allowed to flex to both axial sides of the outer circumference, a cup-shaped valve case having an annular opposing portion that forms a gap allowing the passage of a liquid facing the outer circumference of the annular valve body, a valve seat for supporting the inner circumference of the annular valve body, and a valve stopper for restricting the flexure of the annular valve seat (for example, Patent Document 1).

[0003] According to the damping valve configured as described above, in a speed range where the expansion and contraction speed (piston speed) of the shock absorber is low and the annular valve body does not flex, the gap formed between the outer circumference of the annular valve body and the annular opposing portion of the valve case is maintained in a narrow state. On the other hand, when the piston speed of the shock absorber increases and the outer circumference side of the annular valve body flexes, the outer circumference end of the annular valve body separates from the annular opposing portion, so the gap widens.

[0004] Therefore, in a shock absorber that uses the above-described damping valve to generate a damping force, in a very low speed range where the expansion and contraction speed is lower than the low speed, the damping coefficient is increased to quickly start the damping force in proportion to the expansion and contraction speed, and in the low speed range, the damping coefficient can be made smaller than in the very low speed range, and damping force characteristics suitable for improving the ride comfort of a vehicle can be realized.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Conventional damping valves are used to generate damping force when the shock absorber expands and contracts at very low speeds, and are installed in series with leaf valves that generate damping force when the shock absorber expands and contracts at speeds above low speed.

[0007] Specifically, the damping valve is mounted on the outer circumference of the piston rod, stacked together with a stacked leaf valve that opens and closes a port on the piston, which divides the inside of the cylinder of the shock absorber into an extension chamber and a compression chamber.

[0008] Therefore, since such damping valves are stacked on top of the piston and leaf valves and installed in the shock absorber, the overall length of the piston section, including the piston, leaf valve, and damping valves, becomes longer, which leads to a problem of shorter stroke length in the shock absorber.

[0009] Furthermore, manufacturing shock absorbers with different cylinder diameters requires preparing multiple valve cases corresponding to the cylinder diameter, which makes parts management cumbersome and increases manufacturing costs.

[0010] Furthermore, because the damping valve consists of many parts in addition to the annular valve body and valve case, such as spacers and valve stoppers, the damping valve is difficult to assemble and requires a lot of effort.

[0011] Therefore, the present invention aims to provide a damping valve and shock absorber that can shorten the overall length, are inexpensive, and are easy to assemble. [Means for solving the problem]

[0012] To solve the above problems, the damping valve of the present invention comprises a valve seat member having an annular recess, a port opening at the bottom of the recess, an annular valve seat rising from the outer circumference of the recess, and an annular opposing portion having an inner circumferential surface facing the recess; a sub-valve disposed within the recess spaced apart from the bottom of the recess, which is annular and forms an annular gap between its outer circumferential surface and the opposing portion, with its outer circumferential side being a free end and allowing it to deflect in a direction away from the valve seat member within the recess; and a leaf valve which is annular and stacked axially spaced apart on the side of the sub-valve opposite the valve seat member, with its outer circumferential side being a free end and allowing it to deflect and seat on and off the valve seat.

[0013] In this damping valve configuration, the valve seat member, which has a valve seat on which the leaf valve sits and unseats, also houses the sub-valve and has a recess that allows for the deflection of the sub-valve, as well as a counter portion that faces the outer circumference of the sub-valve. Therefore, the valve seat member can function as the valve seat for both the sub-valve and the leaf valve. In this way, the damping valve allows the valve seats for both the sub-valve and the leaf valve to be integrated into a single valve seat member, reducing the number of parts and shortening the overall length.

[0014] Furthermore, the valve seat member in the damping valve may have an inclined surface between the opposing portion and the seat surface on which the leaf valve of the valve seat sits and dissipates. When the valve seat member has an inclined surface in this way, when the sub-valve flexes, the flow area of ​​the gap between the outer circumference of the sub-valve and the valve seat member increases rapidly, preventing the sub-valve from affecting the damping force when the buffer contracts at low speed. In addition, when the valve seat member is manufactured by sintering, by providing an inclined surface between the seat surface of the valve seat and the opposing portion which is composed of a cylindrical surface perpendicular to the seat surface, a fragile right-angle corner is not formed between the opposing portion and the inclined surface. Thus, with a damping valve, the durability of the valve seat member can be improved, and the opposing portion can be positioned closer to the seat surface of the valve seat in the radial direction, improving the design freedom of the inner diameter of the opposing portion and the outer diameter of the sub-valve.

[0015] Furthermore, the damping valve may be provided with a valve stopper positioned between the sub-valve and the leaf valve, spaced apart from the sub-valve, and which is annular in shape and allows for deflection on its outer circumference. The valve stopper restricts the deflection of the sub-valve when the outer circumference of the sub-valve deflects in a direction away from the valve seat member and makes contact. With a damping valve configured in this way, when the sub-valve deflects in a direction away from the valve seat member while making contact with the valve stopper, it is supported not only by the valve stopper but also by the leaf valve, thereby suppressing the undulating deformation of the sub-valve and reducing the fatigue of the sub-valve.

[0016] Furthermore, the damping valve may include a ring attached to the outer wall of the outer circumference that forms the recess, with the opposing portion formed on the inner surface of the ring. With a damping valve configured in this way, when the valve seat member body, which is the part of the valve seat member other than the ring, is manufactured by sintering, a ring with high dimensional accuracy of the inner diameter can be attached to the outer wall of the recess. This makes it easier to control the dimensions of the annular gap between the sub-valve and the ring, and makes it easier to achieve the desired damping force characteristics.

[0017] Furthermore, the damping valve may have a bottomed cylindrical cup in which a valve seat member is housed in a recess, with an annular spacer smaller in diameter than the sub-valve interposed between the sub-valve and the bottom of the cup and between the sub-valve and the leaf valve, respectively, and may also include a shaft member that holds the inner circumference of the valve seat member, cup, sub-valve, spacer and leaf valve.

[0018] With a damping valve configured in this way, when the valve seat member body, which is the part of the valve seat member other than the cup, is manufactured by sintering, it is sufficient to house a cup with high dimensional accuracy of the inner diameter of the cylindrical part in the recess. This makes it easier to control the dimensions of the annular gap between the sub-valve and the cylindrical part of the cup, and also makes it easier to achieve the desired damping force characteristics.

[0019] Further, the shock absorber includes a telescopic shock absorber body having a cylindrical outer shell and a rod that is movably inserted into the outer shell, and a damping valve. The valve seat member partitions two working chambers that are communicated by ports within the shock absorber body. According to the shock absorber configured as described above, the overall length of the damping valve can be shortened, so that it is easy to ensure the stroke length and the assembly property is also improved by reducing the number of parts of the damping valve.

Effects of the Invention

[0020] According to the damping valve and the shock absorber of the present invention, the overall length can be shortened, and it can be made inexpensive and the assembly property can be improved.

Brief Description of the Drawings

[0021] [Figure 1] It is a longitudinal sectional view of a shock absorber provided with a damping valve according to an embodiment of the present invention. [Figure 2] It is a sectional view of a damping valve according to an embodiment of the present invention. [Figure 3] It is an enlarged view of a part of a damping valve according to an embodiment of the present invention. [Figure 4] It is a diagram showing the damping force characteristics of a shock absorber provided with a damping valve according to an embodiment of the present invention. [Figure 5] It is a sectional view of a damping valve according to a first modification of an embodiment of the present invention. [Figure 6] It is a sectional view of a damping valve according to a second modification of an embodiment of the present invention.

Modes for Carrying Out the Invention

[0022] The present invention will be described below based on the embodiments shown in the figures. As shown in Figures 1 and 2, the damping valve 1 of this embodiment comprises a valve case 2 as a valve seat member, a sub-valve 3, and a leaf valve 4, and is provided within an expandable and contractible shock absorber body 10 having an outer shell 14 and a rod 12 that is movably inserted into the outer shell 14, and is used as the base valve of the shock absorber D. In the case of this shock absorber D, it is used interposed between the vehicle body and the axle in a vehicle (not shown) to suppress vibrations of the vehicle body and wheels.

[0023] The damping valve 1 and the shock absorber D will be described in detail below. As shown in Figure 1, the shock absorber body 10 comprises a cylinder 11, a bottomed cylindrical outer shell 14 covering the outer circumference of the cylinder 11, a rod 12 located inside the outer shell 14 and movably inserted into the cylinder 11, and a piston 13 connected to the rod 12 and movably inserted into the cylinder 11, which divides the inside of the cylinder 11 into an extension chamber R1 and a compression chamber R2, which serve as working chambers.

[0024] A bracket (not shown) is provided at the base end of the rod 12, which is the upper end in Figure 1, and the rod 12 is connected to one of the vehicle body and the axle via this bracket (not shown). A bracket (not shown) is also provided at the bottom 14a of the outer shell 14, and the outer shell 14 is connected to the other of the vehicle body and the axle via this bracket (not shown).

[0025] In this way, the shock absorber body 10 in the shock absorber D is interposed between the vehicle body and the axle. When the vehicle travels on an uneven road surface, causing the wheels to vibrate up and down relative to the vehicle body, the rod 12 moves in and out of the outer shell 14, and the piston 13 moves up and down (axially) within the cylinder 11.

[0026] Furthermore, the shock absorber body 10 closes the upper ends of the cylinder 11 and the outer shell 14 and is equipped with an annular rod guide 15 through which the rod 12 is slidably inserted. Thus, the inside of the cylinder 11 and the outer shell 14 is a sealed space.

[0027] Furthermore, a valve case 2, which serves as a valve seat member, is fitted to the lower end of the cylinder 11. The upper end of the outer shell 14 in Figure 1 is crimped from the outer circumference and bent inward, and together with the bottom 14a, it holds the rod guide 15, cylinder 11, and valve case 2 housed within the outer shell 14.

[0028] The valve case 2 separates the compression chamber R2 within the cylinder 11 from the reservoir R formed in the annular gap between the cylinder 11 and the outer shell 14. The extension chamber R1 and compression chamber R2 within the cylinder 11 are filled with liquid, and the reservoir R is filled with gas and liquid. The liquid filled in the buffer body 10 may be hydraulic oil, water, aqueous solution, or other liquids.

[0029] When the buffer D extends, the rod 12 retracts from the cylinder 11, and as the volume of the retracted rod 12 increases the volume inside the cylinder, liquid is supplied from the reservoir R into the cylinder 11. Conversely, when the buffer D contracts, the rod 12 retracts into the cylinder 11, and as the volume of the retracted rod 12 decreases the volume inside the cylinder, liquid is discharged from the cylinder 11 into the reservoir R.

[0030] Thus, the buffer D in this embodiment is configured as a single-rod, double-cylinder type buffer, and compensates for the volume of the rod 12 moving in and out of the cylinder 11 by supplying and discharging liquid from the reservoir R into the cylinder 11.

[0031] The rod 12 includes a small-diameter portion 12a provided at the tip, a stepped portion 12c provided at the boundary between the small-diameter portion 12a and the large-diameter portion 12b located above the small-diameter portion 12a in Figure 1, and a threaded portion 12d provided on the outer circumference of the tip of the small-diameter portion 12a.

[0032] Next, the piston 13 is annular in shape and fitted onto the outer circumference of the small-diameter portion 12a of the rod 12. It is fixed to the rod 12 by a piston nut 21 that is screwed onto the threaded portion 12d of the rod 12, and can move together with the rod 12 in the axial direction (up and down in Figure 1). More specifically, the piston 13 slides against the inner circumference of the cylinder 11, dividing the inside of the cylinder 11 into an upper extension chamber R1 and a lower compression chamber R2 in Figure 1, and is provided with an extension port 13a and a compression port 13b that connect the extension chamber R1 and the compression chamber R2.

[0033] On the lower surface of the piston 13 in Figure 1, there is an extension damping valve 16, which is an annular laminated leaf valve that is fixed on its inner circumference to the small diameter portion 12a of the rod 12, allowing the outer circumference to deflect and opening and closing the extension port 13a, and an annular spacer 17 that sets the position of the pivot point for the deflection of the extension damping valve 16.

[0034] Furthermore, on the upper surface of the piston 13 in Figure 1, there is an annular compression check valve 18 that is fixed on its inner circumference to the small diameter portion 12a of the rod 12, allowing for deflection on the outer circumference and opening and closing the compression port 13b, and an annular spacer 19 that sets the position of the pivot point for the deflection of the compression check valve 18.

[0035] These spacers 19, compression check valve 18, piston 13, extension damping valve 16, and spacer 17 are then assembled in order around the outer circumference of the small diameter portion 12a of the rod 12, and are then fixed to the rod 12 by being sandwiched between the piston nut 21, which is screwed onto the threaded portion 12d at the tip of the rod 12, and the stepped portion 12c of the rod 12.

[0036] The extension damping valve 16 is a laminated leaf valve constructed by stacking multiple annular plates, the inner circumference of which is fixed to the rod 12 as described above and stacked on the lower end of the piston 13 in Figure 1, opening and closing the outlet end of the extension port 13a of the piston 13, and the outer circumference is equipped with a notched orifice 16a that normally connects the extension port 13a to the compression chamber R2. Therefore, when the opening end of the extension port 13a is closed, the extension damping valve 16 connects the extension port 13a to the compression chamber R2 only through the notched orifice 16a.

[0037] Furthermore, when the extension-side damping valve 16 has its extension-side port side facing forward, the extension-side chamber R1 acts on the front side via the extension-side port 13a. Inside Pressure acts on the back side of the pressure chamber R2 Inside When the pressure becomes higher than the pressure between the two sides and the pressure difference reaches the valve opening pressure, the outer circumference flexes to open the valve and release the extension port 13a. When the extension damping valve 16 flexes and separates its outer circumference from the piston 13, it forms an annular gap between itself and the piston 13, and through this gap, the extension port 13a communicates with the pressure chamber R2, providing resistance to the flow of liquid passing through the extension port 13a. In this embodiment of the buffer D, the extension damping valve 16 opens when the extension speed of the buffer D is in the high-speed range, providing resistance to the flow of liquid from the extension chamber R1 to the pressure chamber R2 through the extension port 13a.

[0038] The other compression side check valve 18 is constructed by stacking multiple annular plates, the inner circumference of which is fixed to the rod 12 as described above and stacked on the upper end of the piston 13 in Figure 1, opening and closing the outlet end of the compression side port 13b of the piston 13. The compression side check valve 18 is located in the compression side chamber R2 Inside The pressure in the extension chamber R1 InsideWhen the pressure is higher than the pressure between the two sides and the pressure difference reaches the opening pressure, the outer circumference flexes to open the valve and open the pressure-side port 13b. The pressure-side check valve 18 then flexes its outer circumference and separates from the piston 13, opening the pressure-side port 13b and allowing the liquid to flow through the pressure-side port 13b from the pressure-side chamber R2 to the extension-side chamber R1. The opening pressure of the pressure-side check valve 18 is set to be very low, and the pressure-side check valve 18 is designed not to provide much resistance to the liquid flow through the pressure-side port 13b when it is open.

[0039] Furthermore, the extension damping valve 16 is constructed by stacking multiple annular plates, but the number of stacked annular plates is determined by the amount generated in the buffer D. stomach The damping force can be arbitrarily changed, and it may consist of only one annular plate. Similarly, the compression check valve 18 is constructed by stacking multiple annular plates, but the number of stacked annular plates can be arbitrarily changed, and it may consist of only one annular plate. Furthermore, the extension damping valve 16 and the compression check valve 18 may be valves other than those made of annular plates, but using valves made of thin annular plates has the advantage of not increasing the overall length of the piston part of the shock absorber D, making it easier to secure the stroke length of the shock absorber D.

[0040] Furthermore, the extension damping valve 16 and the compression check valve 18 are supported on their inner circumference by spacers 17 and 19, respectively, and deflection of the outer circumference not supported by spacers 17 and 19 is permitted. Therefore, the position of the pivot point for the deflection of the extension damping valve 16 and the compression check valve 18 can be changed by setting the outer diameter of spacers 17 and 19. Note that spacers 17 and 19 may be composed of multiple annular washers.

[0041] Next, the damping valve 1 comprises a valve case 2 as a valve seat member, a sub-valve 3, and a leaf valve 4. The valve case 2 is annular and comprises a base portion 2a that fits onto the lower end of the cylinder 11 in Figure 2, and a cylindrical portion 2b that hangs down from the outer circumference of the lower end of the base portion 2a.

[0042] The base portion 2a of the valve case 2 is provided with a plurality of compression-side damping ports 2c that penetrate the base portion 2a vertically, an annular recess 2d provided at the lower end of the base portion 2a in Figure 2 and connected to the open end of the compression-side damping ports 2c, an annular valve seat 2e at the lower end of the base portion 2a in Figure 2 rising from the outer circumference of the recess 2d, an annular opposing portion 2f having an inner circumferential surface facing the recess 2d, and a plurality of suction ports 2g that penetrate the base portion 2a vertically and are located on the outer circumference side of the compression-side damping ports 2c of the base portion 2a.

[0043] Multiple compression-side damping ports 2c, acting as ports, are provided at equal intervals along the same circumference of the base 2a, penetrating the base 2a vertically and connecting the compression-side chamber R2 with the space within the cylindrical portion 2b. The recess 2d is annular and communicates with the opening end of the compression-side damping port 2c at the lower end in Figure 2. As shown in Figure 3, the recess 2d is formed by an annular bottom 2d1 into which the compression-side damping port 2c opens, an annular tapered inner wall 2d2 that forms the inner circumferential wall of the bottom, and an annular outer wall 2d3 that forms the outer circumferential wall of the bottom and has a circumferential surface perpendicular to the base 2a, with the opening area increasing towards the bottom in Figure 3. Furthermore, an annular inner circumferential sheet surface 2h with a flat surface is provided at the lower end of the base 2a in Figure 2, inside the circumference of the recess 2d.

[0044] As shown in Figure 3, the valve seat 2e is provided so as to protrude downward in Figure 2 from the lower end of the base 2a and the outer circumference of the recess 2d, and comprises an annular seat surface 2e1 on which the leaf valve 4 sits and unseats, and an inclined surface 2e2 connected to the outer circumference of the recess 2d, surrounding the outer circumference of the compression damping port 2c. Since the seat surface 2e1 of the valve seat 2e protrudes downward from the lower end of the base 2a, it is positioned lower than the inner circumferential seat surface 2h on the inner circumference side of the recess 2d in Figure 2. Therefore, when viewed from the base 2a, the seat surface 2e1 is higher than the inner circumferential seat surface 2h, and a height difference is provided between the two. Also, since the bottom 2d1 that forms the recess 2d is positioned above the inner circumferential seat surface 2h in Figure 2, when viewed from the base 2a, the bottom 2d1 is lower than the inner circumferential seat surface 2h, and a height difference is provided between the two.

[0045] Furthermore, in the damping valve 1 of this embodiment, the opposing portion 2f is formed by an outer wall 2d3 having an inner circumferential surface facing the recess 2d formed in the base portion 2a.

[0046] Multiple suction ports 2g are provided at equal intervals along the same circumference of the base 2a, and they penetrate the base 2a vertically, connecting the pressure chamber R2 with the space inside the cylindrical portion 2b.

[0047] The valve case 2 has a base portion 2a fitted to the inner circumference of the lower end of the cylinder 11 in Figure 2, and the lower end of the cylindrical portion 2b abuts against the bottom portion 14a of the outer shell 14. The valve case 2 is sandwiched between the cylinder 11 and the bottom portion 14a of the outer shell 14, separating the pressure chamber R2 inside the cylinder 11 from the reservoir R between the cylinder 11 and the outer shell 14. Multiple notches 2b1 are provided at the lower end of the cylindrical portion 2b of the valve case 2, and the space inside the cylindrical portion 2b of the valve case 2 and the reservoir R are in communication via the notches 2b1. Furthermore, the space inside the cylindrical portion 2b of the valve case 2 and the pressure chamber R2 are in communication via a pressure damping port 2c and an intake port 2g. Thus, the pressure chamber R2 and the reservoir R are in communication via a pressure damping port 2c and an intake port 2g.

[0048] In the damping valve 1 of this embodiment, the sub-valve 3 is a single annular plate with an inner diameter equal to the inner diameter of the base 2a and an outer diameter smaller than the diameter of the inner surface of the opposing portion 2f formed by the outer wall 2d3 of the recess 2d, and is superimposed on the inner circumferential seat surface 2h provided at the lower end of the base 2a in the valve case 2. On the side of the sub-valve 3 opposite the valve seat member, a spacer 5 with an inner diameter equal to the inner diameter of the sub-valve 3 and an outer diameter smaller than the outer diameter of the sub-valve 3, a valve stopper 6 with an inner diameter equal to the inner diameter of the sub-valve 3 and an outer diameter smaller than the outer diameter of the sub-valve 3 and larger than the outer diameter of the spacer 5, a leaf valve 4 that sits away from the seat surface 2e1 of the valve seat 2e, and an annular restricting member 20 that restricts further deflection of the leaf valve 4 when it comes into contact with it are stacked in order. In the above description, the sub-valve 3 is composed of a single annular plate, but the number of annular plates constituting the sub-valve 3 can be changed, and when the sub-valve 3 is composed of multiple annular plates, the outer diameters of each annular plate may be different.

[0049] On the pressure chamber side of the base 2a of the valve case 2, an annular suction check valve 7 and a spacer 8 are stacked, which open and close the opening end of the suction port 2g, which is the upper end in Figure 2. The suction check valve 7 is constructed by stacking multiple annular plates and has a through hole 7a that penetrates the annular plates vertically. Therefore, even when the suction check valve 7 is in contact with the base 2a, the pressure damping port 2c is always in communication with the pressure chamber R2 through the through hole 7a, and the suction check valve 7 does not block the pressure damping port 2c.

[0050] Then, the shaft portion 9b of the guide rod 9, which is a shaft member having a head portion 9a and a shaft portion 9b, is inserted into the inner circumference of the spacer 8, the suction check valve 7, the base portion 2a of the valve case 2, the sub-valve 3, the spacer 5, the valve stopper 6, the leaf valve 4, and the regulating member 20. The spacer 8, the suction check valve 7, the base portion 2a of the valve case 2, the sub-valve 3, the spacer 5, the valve stopper 6, the leaf valve 4, and the regulating member 20 are clamped between the head portion 9a and the tip of the shaft portion 9b by nuts 30.

[0051] The sub-valve 3 is fixed by being sandwiched between the spacer 5 and the inner circumferential seat surface 2h of the base 2a, with its outer circumference being a free end and allowing deflection of the outer circumference. A height difference is provided between the inner circumferential seat surface 2h of the base 2a and the bottom 2d1 that forms the recess 2d, and a height difference is also provided between it and the seat surface 2e1 on which the leaf valve 4 sits and dissipates. A spacer 5 and a valve stopper 6 are provided between the leaf valve 4 and the sub-valve 3, and a gap is formed between the sub-valve 3 and the leaf valve 4 that allows deflection of the outer circumference of the sub-valve 3. By being stacked on the spacer 5, the sub-valve 3 is positioned spaced apart from the bottom 2d1 in the recess 2d, and deflection in the downward direction in Figure 3, which is the direction away from the valve case 2, is allowed without blocking the compression damping port 2c which acts as a port.

[0052] The spacer 5 has an outer diameter smaller than the outer diameter of the sub-valve 3, and the outer edge of the end face facing the sub-valve 3 forms a fulcrum for the deflection of the sub-valve 3 in the direction away from the valve case 2. Therefore, the sub-valve 3 can be deflected downward in Figure 2 on its outer circumference, using the aforementioned outer edge of the spacer 5 as a fulcrum. The fulcrum for the deflection of the sub-valve 3 can be tuned by setting the outer diameter of the spacer 5, and the amount of deflection before the sub-valve 3 contacts the valve stopper 6 can be tuned by changing the number of stacked spacers or the thickness of the spacer 5.

[0053] Furthermore, the sub-valve 3 can bend upward in Figure 2 on its outer circumference, using the outer edge of the inner circumferential seat surface 2h as a pivot point. Even when the sub-valve 3 is bent upward in Figure 2, a sufficient height difference is provided between the bottom 2d1 of the recess 2d and the inner circumferential seat surface 2h so that the compression damping port 2c is not blocked.

[0054] When the sub-valve 3 is not flexed and is in the initial mounting state shown in Figure 3, its outer surface faces the inner surface of the annular opposing portion 2f, and a predetermined annular gap P is maintained between it and the opposing portion 2f. In this embodiment of the damping valve 1, the annular gap P formed between the facing sub-valve 3 and the opposing portion 2f is very narrow, and the opening area of ​​this annular gap P is smaller than the opening area of ​​the notched orifice 4a provided in the leaf valve 4, which will be described later.

[0055] The valve stopper 6 is made of an elastic annular plate whose outer diameter is larger than the outer diameter of the spacer 5 and smaller than the outer diameter of the sub-valve 3. Therefore, when the outer circumference of the sub-valve 3 bends downward in Figure 2 and comes into contact with the valve stopper 6, the valve stopper 6 comes into contact with the side of the sub-valve 3 that is not the valve seat member, supporting the sub-valve 3 and restricting its bending.

[0056] The leaf valve 4 is a laminated leaf valve constructed by stacking multiple annular plates. As described above, its inner circumference is fixed to the valve case 2 by a guide rod 9, and its outer circumference is seated on the seat surface 2e1 of the valve seat 2e provided in the valve case 2. Of the annular plates constituting the leaf valve 4, the annular plate stacked at the top in Figure 2 and seated on the valve seat 2e has an outer diameter larger than the outer diameter of the sub-valve 3 and is equipped with a notched orifice 4a on its outer circumference. Therefore, when the leaf valve 4 is seated on the valve seat 2e, the compression-side damping port 2c, which is surrounded by the valve seat 2e, is connected to the reservoir R only through the notched orifice 4a.

[0057] Then, when the leaf valve 4 has the valve seat member side facing the valve case side as the front, the compression chamber R2 acts on the front side via the compression damping port 2c. Inside The pressure and the reservoir R acting on the back side internal pressure When the differential pressure reaches the valve opening pressure, the leaf valve 4 flexes its outer circumference and separates from the valve seat 2e. When the leaf valve 4 separates from the valve seat 2e, it forms an annular gap between itself and the valve seat 2e, and through this gap, it connects the pressure-side damping port 2c to the reservoir R, thereby providing resistance to the flow of liquid passing through the pressure-side damping port 2c. In the damping valve 1 of this embodiment, the leaf valve 4 opens when the contraction speed of the buffer D is in the high-speed range, providing resistance to the flow of liquid passing through the pressure-side damping port 2c from the pressure-side chamber R2 to the reservoir R. Furthermore, the leaf valve 4 is configured so that the pressure-side damping port 2c is a one-way passage that only allows the flow of liquid from the pressure-side chamber R2 to the reservoir R.

[0058] Furthermore, the valve seat 2e protrudes downward in Figure 2 from the lower end of the valve stopper 6, which is the opposite end of the valve seat to the inner circumference of the leaf valve 4, creating a height difference between the two. When the leaf valve 4 is placed on the valve case 2 along with the sub-valve 3, spacer 5, and valve stopper 6, and its inner circumference is fixed to the outer circumference of the shaft portion 9b of the guide rod 9, the outer circumference flexes due to this height difference. In this way, the leaf valve 4 is given an initial flexure in advance and presses itself against the valve seat 2e with the elastic force it exerts. Therefore, the leaf valve 4 will not open until the force that flexes the leaf valve 4 due to the differential pressure between the pressure chamber R2 and the reservoir R overcomes the pressing force due to the aforementioned elastic force, and this differential pressure at the time of opening becomes the opening pressure of the leaf valve 4. Thus, the opening pressure of the leaf valve 4 can be adjusted by the flexural rigidity of the leaf valve 4 and the amount of initial flexure applied to the leaf valve 4.

[0059] Furthermore, the leaf valve 4 is constructed by stacking multiple annular plates, and the number of stacked annular plates is determined by the amount generated in the buffer D. stomach It can be arbitrarily changed according to the damping force and may consist of only a single annular plate. Alternatively, instead of providing a notched orifice 4a in the leaf valve 4, or in addition, a recess that functions as an orifice may be provided in the valve seat 2e by stamping it or the like.

[0060] The suction check valve 7 is fixed to the guide rod 9 along with the spacer 8 as described above, and is stacked on the upper end of the base 2a of the valve case 2 in Figure 2, opening and closing the outlet end of the suction port 2g provided in the valve case 2. The spacer 8 is annular in shape, with an inner diameter set to be the same as the inner diameter of the suction check valve 7, and an outer diameter set to a diameter that does not block the through hole 7a of the suction check valve 7. Therefore, the suction check valve 7 is allowed to deflect upward in Figure 2 on its outer circumference, with the outer edge of the valve seat member side end of the spacer 8 as the pivot point.

[0061] And the suction check valve 7 is reservoir R Inside The pressure in the pressure side chamber R2 InsideWhen the pressure difference between the two reaches the opening pressure, the outer circumference flexes to open the valve, opening the suction port 2g. The suction check valve 7 then flexes its outer circumference, separating from the valve case 2, opening the suction port 2g and allowing the liquid to flow from the reservoir R to the pressure chamber R2. The opening pressure of the suction check valve 7 is set to be very low, and the suction check valve 7 is designed not to provide much resistance to the liquid flow through the suction port 2g when it is open. The suction check valve 7 is constructed by stacking multiple annular plates, but the number of stacked annular plates can be arbitrarily changed, and it may be constructed with only one annular plate. In addition, a notched orifice may be provided in the suction check valve 7, or a recess that functions as an orifice may be provided in the valve seat on which the suction check valve 7 sits and unseats.

[0062] The damping valve 1 and buffer D of this embodiment are configured as described above. The operation of the damping valve 1 and buffer D will be described below. First, the case in which the buffer D exhibits extension operation will be described. In Figure 1, when the buffer D is in extension operation, the rod 12 moves upward relative to the cylinder 11 and outer shell 14, the piston 13 moves upward relative to the cylinder 11 in Figure 1, compressing the extension chamber R1 and expanding the pressure chamber R2. When the extension speed of the buffer D is low, the difference between the pressure in the compressed extension chamber R1 and the pressure in the expanding pressure chamber R2 does not reach the opening pressure of the extension damping valve 16, so the liquid in the extension chamber R1 moves to the pressure chamber R2 through the extension port 13a and notched orifice 16a. Furthermore, in the expanding pressure chamber R2, the rod 12 moves out of the cylinder 11, resulting in a shortage of liquid equivalent to the volume of the rod 12 moving out of the cylinder 11. However, the suction check valve 7 opens, and the shortage of liquid is supplied from the reservoir R to the pressure chamber R2 via the suction port 2g. When the buffer D extends, the suction check valve 7 opens quickly in this way, opening the suction port 2g. As a result, the liquid attempting to move from the reservoir R to the pressure chamber R2 passes through the suction port 2g without passing through the notched orifice 4a, the annular gap P between the sub-valve 3 and the opposing part 2f, and the pressure damping port 2c.

[0063] Thus, when the extension speed of the buffer D is low, the buffer D generates a damping force that hinders the extension operation of the buffer D by resisting the flow of liquid through the extension port 13a via the notched orifice 16a. Therefore, when the buffer D extends at a low speed, the extension damping force characteristic, which is the characteristic of the damping force generated by the buffer D with respect to the piston speed, becomes a characteristic that is proportional to the square of the piston speed, which is unique to orifices, as shown in Figure 4.

[0064] Furthermore, when the extension speed of the buffer D increases, the difference between the pressure in the compressed extension chamber R1 and the pressure in the expanding compression chamber R2 reaches the opening pressure of the extension damping valve 16, causing the extension damping valve 16 to open and the extension port 13a to open. In this way, when the extension speed of the buffer D increases, the buffer D generates a damping force that resists the flow of liquid through the extension port 13a by the extension damping valve 16, thereby hindering the extension operation of the buffer D. Therefore, as shown in Figure 4, the damping force characteristics on the extension side when the buffer D extends at high speed have a lower damping coefficient compared to when it extends at low speed, and exhibit characteristics unique to leaf valves that are proportional to the piston speed.

[0065] Next, we will explain the case when the buffer D exhibits contraction operation. In Figure 1, when the buffer D contracts, the rod 12 moves downward relative to the cylinder 11 and outer shell 14. In this case, the piston 13 moves downward relative to the cylinder 11 in Figure 1, compressing the compression chamber R2 and expanding the extension chamber R1. Due to the contraction operation of the buffer D, the liquid in the compressed compression chamber R2 moves to the expanding extension chamber R1 via the compression port 13b, which is opened by the opening of the compression check valve 18, with little resistance. Also, when the buffer D contracts, the rod 12 enters the cylinder 11, so the volume of liquid equivalent to the volume of the rod 12 entering the cylinder 11 becomes excess, and the pressure inside the cylinder 11 rises. Since the pressure in the compression chamber R2 becomes higher than the pressure in the reservoir R, the suction check valve 7 closes and blocks the suction port 2g. Therefore, the excess liquid moves from the compression chamber R2 to the reservoir R via the compression damping port 2c. If the contraction speed of the buffer D is slow, the pressure difference between the compressed pressure chamber R2 and the pressure in the reservoir R does not reach the opening pressure of the leaf valve 4. Therefore, the liquid in the pressure chamber R2 moves to the reservoir R through the pressure damping port 2c, the annular gap P between the sub-valve 3 and the opposing part 2f, and the notched orifice 4a.

[0066] In the damping valve 1, the sub-valve 3 deflects when the rod 12 begins to move in the contraction direction relative to the cylinder 11, and the amount of deflection of the sub-valve 3 increases in proportion to the increase in the contraction speed of the shock absorber D. When the contraction speed of the shock absorber D is close to 0 (zero), such as when it is just starting to move, the amount of deflection of the sub-valve 3 is very small, and in the range from very low speed to low speed, the sub-valve 3 deflects to such an extent that it can no longer face the inner circumferential surface of the opposing part 2f, causing the sub-valve 3 to open. Furthermore, when the contraction speed of the shock absorber D is low or high, the outer circumference of the sub-valve 3 deflects significantly downward in Figure 3, with the outer edge of the spacer 5 as the fulcrum for the deflection. When the sub-valve 3 bends and separates from the opposing part 2f to open, the pressure difference between the pressure-side chamber R2 and the reservoir R, that is, the opening pressure of the sub-valve 3, is lower than the opening pressure of the leaf valve 4. If the contraction speed is in the low-speed range, the sub-valve 3 opens as described above, but the leaf valve 4 does not open, and the liquid moves from the pressure-side chamber R2 to the reservoir R via the annular gap P and the notched orifice 4a.

[0067] Furthermore, if the annular gap P is set to approximately 0 when the sub-valve 3 is directly facing the inner circumferential surface of the opposing portion 2f, a differential pressure will be generated between the compression chamber R2 and the reservoir R immediately after the shock absorber D starts moving. As a result, the shock absorber D can quickly generate damping force when it switches from extension to contraction.

[0068] Thus, when the contraction speed of the buffer D is low or high, the outer circumference of the sub-valve 3 bends significantly downward in Figure 3, and the opening area of ​​the annular gap P created between the downwardly shifted sub-valve 3 and the opposing part 2f becomes larger than the opening area of ​​the notched orifice 4a.

[0069] Therefore, when the contraction speed of buffer D is in the very low speed range and close to 0, the pressure in the pressure chamber R2 will rise. Pressure in the pressure chamber R2 andSince the pressure difference with the pressure in reservoir R does not reach the opening pressure of leaf valve 4, leaf valve 4 does not open and maintains the pressure-side damping port 2c closed. Also, since the pressure difference does not reach the opening pressure of sub-valve 3, even if sub-valve 3 bends, its outer surface faces the range of the axial width of the inner circumference of the opposing part 2f, resulting in a closed state and maintaining an extremely small flow area in the annular gap P between sub-valve 3 and opposing part 2f. The liquid moves from the pressure-side chamber R2 to reservoir R by passing through the pressure-side damping port 2c, the annular gap P, and the notched orifice 4a. However, since the flow area of ​​the annular gap P in the closed sub-valve 3 is smaller than the flow area of ​​the notched orifice 4a, when the contraction speed of buffer D is in the very low speed range, buffer D generates a damping force that hinders contraction mainly due to the resistance that sub-valve 3 imparts to the liquid. Therefore, when the compression speed of the shock absorber D is in the very low speed range, the damping force characteristics on the compression side of the shock absorber D are as shown in Figure 4. The damping coefficient rises very high when the compression speed is near zero, and then decreases as the sub-valve 3 opens. In this way, by generating damping force with the sub-valve 3 when the shock absorber D contracts at a very low speed, sufficient damping force is obtained to suppress vibrations at the beginning of the expansion and contraction of the shock absorber D, which can improve the ride comfort in the vehicle.

[0070] Also When the contraction speed of buffer D is low, buffer D generates a damping force that hinders contraction mainly due to the resistance that the notched orifice 4a imparts to the liquid. Therefore, when the contraction speed of buffer D is low, the damping force characteristics on the compression side of buffer D are proportional to the square of the contraction speed of buffer D, which is characteristic of orifices, as shown in Figure 4, but the damping coefficient is smaller compared to when the contraction speed is in the very low speed range.

[0071] Furthermore, as the contraction speed of buffer D increases and changes from the very low speed range to the low speed range, the compression chamber R2 Inside The pressure and reservoir R InsideSince the pressure difference with the valve case 2 exceeds the opening pressure of the sub-valve 3, the sub-valve 3 bends so that its outer circumference moves out of the axial width range of the inner circumference of the opposing part 2f, downward in Figure 3, and opens, making the flow area of ​​the annular gap P between the sub-valve 3 and the opposing part 2f larger than the flow area of ​​the notched orifice 4a. When the sub-valve 3 bends and can no longer face the opposing part 2f, the outer circumference of the sub-valve 3 comes into contact with the valve seat 2e. Since an inclined surface 2e2 is provided on the inner circumference of the valve seat 2e, when the sub-valve 3 bends, the flow area between it and the valve case 2 increases rapidly, so that the sub-valve 3 does not affect the damping force when the buffer D contracts at low speed.

[0072] Furthermore, the sub-valve 3 is supported by the valve stopper 6 and the leaf valve 4 by bending and contacting them. Since the sub-valve 3 is supported in a bow-shaped bending state at two points where it contacts the valve stopper 6 and the leaf valve 4 in the radial direction, deformation that causes the valve stopper 6 to undulate with a width from the inner circumference to the outer circumference is restricted. If the sub-valve 3 deforms in an undulating manner, a large stress will act on the sub-valve 3, accelerating fatigue. However, since the valve stopper 6 and the leaf valve 4 support the sub-valve 3 at two points on its back surface, this deformation can be prevented, thus reducing fatigue of the sub-valve 3.

[0073] Furthermore, when the contraction speed of the buffer D exceeds the low-speed range and is in the high-speed range, the pressure difference between the pressure in the pressure-side chamber R2 and the pressure in the reservoir R reaches the opening pressure of the leaf valve 4, causing the leaf valve 4 to bend and open, opening the pressure-side damping port 2c. When the contraction speed of the buffer D is high, the difference between the pressure in the pressure-side chamber R2 and the pressure in the reservoir R exceeds the opening pressure of the sub-valve 3, so the sub-valve 3 opens, and the flow area of ​​the annular gap P between the sub-valve 3 and the opposing part 2f increases. The sub-valve 3 then bends together with the valve stopper 6 and the leaf valve 4 while remaining in contact with them. Therefore, it is possible to prevent the sub-valve 3 from narrowing the flow area of ​​the pressure-side damping port 2c when the leaf valve 4 is open and the pressure-side damping port 2c is open. Thus, when the contraction speed of the buffer D is high, the sub-valve 3 bends significantly, and the flow area in the gap between the leaf valve 4 and the valve seat 2e becomes smaller than the flow area in the annular gap P. Therefore, when the contraction speed of the buffer D is high, the buffer D generates a damping force that hinders contraction mainly due to the resistance that the leaf valve 4 imparts to the liquid. Consequently, when the contraction speed of the buffer D is high, the damping force characteristics on the compression side of the buffer D, as shown in Figure 4, are proportional to the contraction speed of the buffer D, which is unique to the leaf valve 4, but the damping coefficient becomes even smaller compared to when the contraction speed is low.

[0074] Thus, in the damping valve 1, the sub-valve 3 is installed between the outlet end of the compression damping port 2c, which acts as a port, and the leaf valve 4, and therefore generates damping force only when the shock absorber D is contracting.

[0075] The damping valve 1 and shock absorber D of this embodiment operate as described above. The damping valve 1 of this embodiment comprises a valve case (valve seat member) 2 having an annular recess 2d, a compression damping port (port) 2c opening at the bottom 2d1 of the recess 2d, an annular valve seat 2e rising from the outer circumference of the recess 2d, and an annular opposing portion 2f having an inner circumferential surface facing the recess 2d; a sub-valve 3 disposed within the recess 2d spaced apart from the bottom 2d1 of the recess 2d, which is annular and forms an annular gap P between its outer circumferential surface and the opposing portion 2f, with its outer circumference being a free end and allowing it to deflect in a direction away from the valve case (valve seat member) 2 within the recess 2d; and a leaf valve 4 which is annular and stacked axially spaced apart on the side opposite the sub-valve 3 to the valve seat member, with its outer circumference being a free end and allowing it to deflect and seat on and off the valve seat 2e.

[0076] In the damping valve 1 configured in this way, the valve case (valve seat member) 2, which has a valve seat 2e on which the leaf valve 4 sits and unseats, houses the sub-valve 3 and also has a recess 2d that allows for deflection of the sub-valve 3 and a facing portion 2f that faces the outer circumference of the sub-valve 3. Therefore, the valve case (valve seat member) 2 can function as a valve seat for both the sub-valve 3 and the leaf valve 4.

[0077] Therefore, in conventional damping valves, a valve case and piston etc. are provided with separate valve seats for the sub-valve and leaf valve, but in the damping valve 1 of this embodiment, the valve seats of both the sub-valve 3 and the leaf valve 4 can be consolidated into a single valve case (valve seat member) 2, reducing the number of parts and shortening the overall length. Furthermore, with the damping valve 1, the valve seats of both the sub-valve 3 and the leaf valve 4 can be consolidated into a single valve case (valve seat member) 2, reducing the number of parts and improving ease of assembly. Moreover, with the damping valve 1, even when manufacturing shock absorbers D with different cylinder diameters 11, only the valve case (valve seat member) 2 needs to be made to match the diameter of the cylinder 11. , Next damping valve andIn comparison, reducing the number of parts simplifies parts management and lowers manufacturing costs. Therefore, according to the damping valve 1 of this embodiment, the overall length can be shortened, making it inexpensive and easy to assemble.

[0078] Furthermore, in the damping valve 1 of this embodiment, the sub-valve 3 in the damping valve 1 is installed between the outlet end of the compression damping port (port) 2c and the leaf valve 4, and is equipped with an intake port 2g that allows only liquid flow in the opposite direction to the compression damping port (port) 2c. Therefore, the sub-valve 3 can generate damping force only when the shock absorber D is contracting. In this way, the sub-valve 3 can be set to be a one-sided valve that generates damping force only during one of the expansion and contraction operations of the shock absorber D, so that the damping force during the expansion operation and the damping force during the contraction operation of the shock absorber D can be set independently.

[0079] Furthermore, the damping valve 1 of this embodiment may also be applied to the piston portion of the shock absorber D. Therefore, for example, similar to the valve case (valve seat member) 2, if the piston 13 described above is provided with a recess connected to the outlet end of the extension port 13a, a valve seat surrounding the outer circumference of the recess and on which the extension damping valve 16 sits and dissipates, and an opposing portion facing the recess, and a sub-valve 3 that allows for outer-circumferential deflection within the recess is installed between the extension damping valve 16 and the piston 13, then when the shock absorber D is extended and extends at a very low speed, the sub-valve 3 can generate a damping force.

[0080] Thus, by applying the damping valve 1 to the piston section and base valve section of the twin-tube type shock absorber D, the sub-valve 3 can exert sufficient damping force to suppress vibrations at the beginning of the shock absorber D's extension and contraction, both during the extension and contraction of the shock absorber D. Furthermore, the sub-valve 3 incorporated in the valve case 2 of the base valve section does not affect the damping force during the extension of the shock absorber D, and the sub-valve 3 incorporated in the piston 13 of the piston section does not affect the damping force during the contraction of the shock absorber D. Therefore, the damping force during the extension and contraction of the twin-tube type shock absorber D can be set independently. In addition, although the damping valve 1 in this embodiment is applied to the base valve of the shock absorber D, it may also be applied only to the piston section. Even if the damping valve 1 is applied only to the piston section in this way, the overall length of the piston section is shortened, resulting in a reduction in the number of parts and enabling a cheaper and easier assembly.

[0081] Thus, the shock absorber D comprises a retractable shock absorber body 10 having a cylindrical outer shell 14 and a rod 12 movably inserted into the outer shell 14, and a damping valve 1. The valve case (valve seat member) 2 divides a compression chamber (operating chamber) R2 and a reservoir (operating chamber) R, which are connected within the shock absorber body 10 by a compression damping port (port) 2c. With the shock absorber D configured in this way, the overall length of the damping valve 1 can be shortened, making it easier to secure the stroke length, and the number of parts of the damping valve 1 is reduced, thus improving ease of assembly.

[0082] Furthermore, in a single-tube type shock absorber where the outer shell forming the outer casing of shock absorber D is used as a cylinder, there is no base valve, and the damping valve is provided only in the piston section. More specifically, in a single-tube type shock absorber, a piston connected to a rod is movably inserted into the inner circumference of the outer shell, and the piston divides the outer shell into an extension chamber and a compression chamber, which are separated by extension ports and compression ports provided on the piston. inA compression leaf valve is provided on the extension side of the piston to open and close the compression port, and an extension leaf valve is provided on the compression side of the piston to open and close the extension port. A free piston is movably inserted into the outer shell to partition an air chamber facing the compression chamber in order to compensate for the volume of the rod that moves in and out of the outer shell. In such a single-tube type shock absorber, the structure of damping valve 1 can be applied to the piston part of the single-tube type shock absorber by providing a recess for the piston and installing a sub-valve between the leaf valve and the piston. When applying the structure of damping valve 1 to the piston part of a single-tube type shock absorber, the sub-valve can be installed between the extension leaf valve and the piston, or between the compression leaf valve and the piston, or both. Furthermore, in such a single-tube type shock absorber, if a sub-valve is provided between the extension leaf valve and the piston, and between the compression leaf valve and the piston, the sub-valve can allow both liquid flow from the extension chamber to the compression chamber and liquid flow from the compression chamber to the extension chamber, and its outer circumference can bend toward both the piston and the leaf valve. Therefore, if an orifice is formed in the extension leaf valve or compression leaf valve on which the sub-valve is provided, it can function as a valve that generates damping force both during the extension and contraction operation of the shock absorber. In this way, even if the structure of damping valve 1 is applied to a single-tube type shock absorber, one piston functions as a valve seat member for both the sub-valve and the leaf valve, so the overall length of the piston can be shortened, and it becomes easier to secure the stroke length of the shock absorber.

[0083] Furthermore, in the damping valve 1 of this embodiment, the valve case (valve seat member) 2 is provided with an inclined surface 2e2 between the opposing portion 2f and the seat surface 2e1 on which the leaf valve 4 of the valve seat 2e sits and dissipates. Because the valve case (valve seat member) 2 is provided with an inclined surface 2e2 in this way, when the sub-valve 3 flexes, the flow area of ​​the gap between the outer circumference of the sub-valve 3 and the valve case (valve seat member) 2 increases rapidly, so that the sub-valve 3 does not affect the damping force when the shock absorber D contracts at low speed.

[0084] Furthermore, when the valve case (valve seat member) 2 is manufactured by sintering, by providing an inclined surface 2e2 between the seat surface 2e1 of the valve seat 2e and the opposing portion 2f which is composed of a cylindrical surface perpendicular to the seat surface 2e1, a fragile right-angle corner is not formed between the opposing portion 2f and the seat surface 2e1. Therefore, according to the damping valve 1 of this embodiment, the durability of the valve seat (valve seat member) 2 can be improved. In addition, when the valve case (valve seat member) 2 is manufactured by sintering, by providing an inclined surface 2e2 between the opposing portion 2f and the seat surface 2e1, the durability of the valve seat (valve seat member) 2 is improved. Therefore, according to the damping valve 1, the opposing portion 2f can be positioned radially close to the seat surface 2e1 of the valve seat 2e, thereby improving the design freedom of the inner diameter of the opposing portion 2f and the outer diameter of the sub-valve 3. In this embodiment, the inclined surface 2e2 is a tapered surface with a constant gradient in cross-section, but it may be a curved surface or an inclined surface with a gradually changing gradient.

[0085] Furthermore, the damping valve 1 of this embodiment is positioned between the sub-valve 3 and the leaf valve 4, spaced apart from the sub-valve 3. The valve stopper 6 is annular in shape, allowing for deflection on its outer circumference, and restricts the deflection of the sub-valve 3 when the outer circumference of the sub-valve 3 deflects in a direction away from the valve case (valve seat member) 2 and makes contact with it. With the damping valve 1 configured in this way, when the sub-valve 3 deflects in a direction away from the valve case (valve seat member) 2 while making contact with the valve stopper 6, it is supported not only by the valve stopper 6 but also by the leaf valve 4, thereby suppressing the undulating deformation of the sub-valve 3 and reducing the fatigue of the sub-valve 3.

[0086] As described above, the outer wall 2d3 on the outer circumference side of the recess 2d of the valve case 2, which serves as the valve seat member, is positioned opposite the outer surface of the sub-valve 3 and forms an annular gap P between it and the outer circumference of the sub-valve 3, forming an opposing portion 2f. However, as shown in the first modified example damping valve 1A in Figure 5, the valve case 2 may also comprise a valve seat member body B1 having a recess 2d, a valve seat 2e, and a compression damping port 2c as a port, and a ring 31 that forms an opposing portion 2f on the inner circumference of the outer wall 2d3 on the outer circumference of the recess 2d in the valve seat member body B1.

[0087] The ring 31 is annular in shape, with an inner diameter larger than the outer diameter of the sub-valve 3, and is press-fitted into the inner circumference of the outer wall 2d3 of the recess 2d, thereby fixing it within the recess 2d. Thus, the valve case 2 is equipped with the ring 31, with the inner surface of the ring 31 facing the outer surface of the sub-valve 3. The axial height of the ring 31 is set to be less than or equal to the depth of the recess 2d, so that the ring 31 does not protrude axially from the recess 2d.

[0088] A sub-valve 3, spacer 5, valve stopper 6, and leaf valve 4 are stacked on the inner circumferential seat surface 2h of the valve case 2, and the inner circumferences of the sub-valve 3, spacer 5, valve stopper 6, and leaf valve 4 are fixed to the outer circumference of the shaft portion 9b of the guide rod 9 by a guide rod 9 and a nut 30. Thus, the damping valve 1A in the first modified example differs from the damping valve 1 described above in that the valve case (valve seat member) 2 is equipped with a ring 31 that is mounted on the outer wall 2d3 of the recess 2d, and the inner circumferential surface of the ring 31 is facing the other side.

[0089] In the first modified example configured in this way, the damping valve 1A operates similarly to the damping valve 1, generating a damping force through the sub-valve 3 when the shock absorber D contracts at a very low speed. Furthermore, in the damping valve 1A of the first modified example, the valve case (valve seat member) 2 is equipped with a ring 31 that functions as the valve seat of the sub-valve 3 and also with a valve seat 2e of the leaf valve 4. Therefore, similar to the damping valve 1, the overall length can be shortened and the number of parts can be reduced, improving ease of assembly. In addition, when the valve seat member body B1, which is the part of the valve case (valve seat member) 2 other than the ring 31, is manufactured by sintering, the ring 31 with high dimensional accuracy of the inner diameter can be mounted on the outer wall 2d3 of the recess 2d. Therefore, with the damping valve 1A, dimensional control of the annular gap P between the sub-valve 3 and the ring 31 becomes easier, and the desired damping force characteristics can be easily achieved. Furthermore, even if the valve case (valve seat member) 2 is composed of the valve seat member body B1 and the ring 31, the valve case (valve seat member) 2 can be manufactured by fitting the ring 31 into the recess 2d, thus improving ease of assembly.

[0090] Furthermore, as shown in the second modified example damping valve 1B in Figure 6, a cup 32 may be housed in the recess 2d instead of the ring 31, with the cup 32 serving as the opposing portion. Specifically, the valve case (valve seat member) 2 comprises a valve seat member body B2 having a recess 2d and a cup 32.

[0091] The valve seat member body B2 comprises a base portion 2a and a cylindrical portion 2b hanging down from the outer circumference of the lower end of the base portion 2a. The base portion 2a is provided with a plurality of compression-side damping ports 2c as ports that penetrate the base portion 2a vertically, an annular recess 2d provided at the lower end of the base portion 2a in Figure 6 and connected to the open end of the compression-side damping ports 2c, an annular valve seat 2e at the lower end of the base portion 2a in Figure 6 rising from the outer circumference of the recess 2d, an annular opposing portion 2f having an inner circumferential surface facing the recess 2d, and a plurality of suction ports 2g that penetrate the base portion 2a vertically and are located on the outer circumference side of the compression-side damping ports 2c of the base portion 2a.

[0092] The recess 2d is annular and communicates with the opening at the lower end of the compression damping port 2c in Figure 6. As shown in Figure 6, the recess 2d is formed by an annular bottom 2d4 into which the compression damping port 2c opens, and an annular outer wall 2d5 that forms the outer circumferential wall of the bottom 2d4 and has a circumferential surface perpendicular to the base 2a. The valve case 2 of the damping valve 1B differs from the damping valve 1 in that the bottom 2d4 of the recess 2d extends to the inner circumference of the base 2a.

[0093] The cup 32 is a bottomed cylindrical shape and comprises an annular bottom portion 32a, a cylindrical portion 32b rising from the outer circumference of the bottom portion 32a, and a plurality of arc-shaped holes 32c provided in the bottom portion 32a. The inner diameter of the bottom portion 32a is the same as the inner diameter of the base portion 2a, so that when the cup 32 is inserted into the recess 2d and the bottom portion 32a is placed on the bottom portion 2d4 of the recess 2d, each compression damping port 2c faces one of the holes 32c, preventing the compression damping ports 2c from being blocked by the cup 32. Furthermore, the axial height of the cup 32 is set to be less than or equal to the depth of the recess 2d, so that the cylindrical portion 32b of the cup 32 does not protrude axially from the recess 2d.

[0094] The bottom 32a of the cup 32 housed in the recess 2d of the valve seat member body B2 is stacked in order with respect to the annular spacer 33, the sub-valve 3, the spacer 5, the valve stopper 6, and the leaf valve 4, which are smaller in diameter than the sub-valve 3. The valve seat member body B2, the cup 32, the spacer 33, the sub-valve 3, the spacer 5, the valve stopper 6, and the leaf valve 4 are held in place by a guide rod 9 inserted into the inner circumference and a nut 30, and fixed to the outer circumference of the shaft portion 9b.

[0095] In the damping valve 1B assembled in this manner, the spacer 33 positions the sub-valve 3 at a distance from the cup 32, so that the outer circumference of the sub-valve 3 faces the inner surface of the cylindrical portion 32b of the cup 32. The inner surface of the cylindrical portion 32b of the cup 32 functions as a counter surface that forms an annular gap P between it and the outer surface of the sub-valve 3. Furthermore, even when the sub-valve 3 is stacked on the spacer 33, the height of the lower end of the sub-valve 3 as viewed from the valve case 2 side is lower than the height of the lower end of the seat surface 2e1 of the valve seat 2e in Figure 6, and the outer circumference of the sub-valve 3 is allowed to deflect in the direction away from the valve case 2 within the recess 2d.

[0096] As described above, the damping valve 1B in the second modified example has a valve case (valve seat member) 2 having a bottomed cylindrical cup 32 housed in a recess 2d, with the opposing portion formed by the cylindrical portion 32b of the cup 32, and annular spacers 5 and 33, which are smaller in diameter than the sub-valve 3, interposed between the sub-valve 3 and the bottom portion 32a of the cup 32 and between the sub-valve 3 and the leaf valve 4, respectively, and comprises a guide rod (shaft member) 9 that holds the inner circumference of the valve case (valve seat member) 2, cup 32, sub-valve 3, spacers 5 and 33 and the leaf valve 4.

[0097] In the second modified example configured in this way, the damping valve 1B operates similarly to the damping valve 1, generating a damping force through the sub-valve 3 when the shock absorber D contracts at a very low speed. Furthermore, in the damping valve 1B of the second modified example, the valve case (valve seat member) 2 is equipped with a cup 32 that functions as the valve seat of the sub-valve 3 and also with a valve seat 2e of the leaf valve 4. Therefore, similar to the damping valve 1, the overall length can be shortened and the number of parts can be reduced, improving ease of assembly. In addition, when the valve seat member body B2, which is the part of the valve case (valve seat member) 2 other than the cup 32, is manufactured by sintering, it is sufficient to house the cup 32, which has high dimensional accuracy in the inner diameter of the cylindrical portion 32b, within the recess 2d. Thus, with the damping valve 1B, dimensional control of the annular gap P between the sub-valve 3 and the cylindrical portion 32b of the cup 32 becomes easier, and it becomes easier to achieve the desired damping force characteristics. Furthermore, even if the valve case (valve seat member) 2 is composed of a valve seat member body B2 and a cup 32, the valve case (valve seat member) 2 can be manufactured by housing the cup 32 in the recess 2d and fixing them with a guide rod (shaft member) 9, thereby improving ease of assembly. Note that the damping valves 1A and 1B may also be applied to the piston portion of the shock absorber D.

[0098] Although preferred embodiments of the present invention have been described in detail above, modifications, alterations, and changes are permitted as long as they do not deviate from the scope of the claims. [Explanation of symbols]

[0099] 1... Damping valve, 2... Valve case (valve seat member), 2c... Compression side damping port (port), 2d... Recess, 2d1... Bottom, 2d3... Outer wall, 2e... Valve seat, 2e1... Seat surface, 2e2... Inclined surface, 2f... Opposing part, 3... Sub-valve, 4... Leaf valve, 5, 33... Spacer, 6... Valve stopper, 9... Guide rod (shaft member), 10... Shock absorber body, 12... Rod, 14... Outer shell, 31... Ring, 32... Cup, 32b... Cylindrical part, B1, B2... Valve seat member body, D... Shock absorber, R... Reservoir (actuating chamber), R2... Compression side chamber (actuating chamber)

Claims

1. A valve seat member comprising an annular recess, a port opening at the bottom of the recess, an annular valve seat rising from the outer circumference of the recess, and an annular opposing portion having an inner circumferential surface facing the recess, A sub-valve is disposed within the recess so as to be spaced apart from the bottom of the recess, is annular in shape, forms an annular gap between its outer surface and the opposing portion, and has its outer surface as a free end, allowing it to deflect in a direction away from the valve seat member within the recess, The system includes a leaf valve which is annular in shape and is positioned axially spaced apart on the side opposite the valve seat member of the sub-valve, with its outer circumference being a free end that allows for bending and is capable of seating onto and off the valve seat. A damping valve characterized by the following features.

2. The valve seat member has an inclined surface between the opposing portion and the seat surface of the valve seat on which the leaf valve sits. The damping valve according to feature 1.

3. The valve seat member has a ring attached to the outer wall on the outer circumference side that forms the recess, The opposing portion is formed on the inner circumferential surface of the ring. The damping valve according to feature 1.

4. The valve seat member has a bottomed cylindrical cup that is housed in the recess, The opposing portion is formed by the cylindrical portion of the cup, An annular spacer smaller in diameter than the sub-valve is interposed between the sub-valve and the bottom of the cup, and between the sub-valve and the leaf valve. The valve seat member, the cup, the sub-valve, the spacer, and the shaft member that holds the inner circumference of the leaf valve are all included. The damping valve according to feature 1.

5. The valve includes an annular valve stopper positioned between the sub-valve and the leaf valve, spaced apart from the sub-valve, which is annular in shape and allows for flexure on its outer circumference, and which restricts the flexure of the sub-valve when the outer circumference of the sub-valve flexes and contacts the valve seat member in a direction away from it. The damping valve according to feature 1.

6. A retractable shock absorber body having a cylindrical outer shell and a rod that is movably inserted into the outer shell, A damping valve according to any one of claims 1 to 5, The valve seat member divides the buffer body into two working chambers that are connected by the port. A buffer characterized by the following features.

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